THE NERVOUS SYSTEM AND CONSCIOUSNESS. 7^7 



which so constantly exhibits dizziness, is associated with marked dis- 

 oi'dei" of the cerebellum. 



In coming to a conclusion respecting the function of this organ, 

 we find that it can not be directly connected with sensation or volition. 

 The sensations appear pronounced and the movements vigorous after 

 destruction of the cerebellum. The marked feature in all deep cere- 

 bellar disorders is the maladjustment of muscular actions to the pres- 

 ervation of equilibrium and to harmonious movements. The con- 

 sciousness of a normal relation between the person and the external 

 world seems overthrown, the violent activities which ensue being 

 plainly attempts to restore this lost feeling. Movements which are 

 voluntarily initiated must be brought into relation with the position 

 of the body in space. The cerebellum is the organ specially concerned 

 with this work. The regulation of all activities that are willed de- 

 pends upon this feeling of the accustomed relation between ourselves 

 and objects. The cerebellum, in some unknown way, makes the pres- 

 ervation of this feeling possible. 



It should be distinctly borne in mind, however, that this conclusion 

 does not necessitate the further one that the cerebellum is itself a seat 

 of consciousness, not even of this consciousness of normal relation. 

 Consciousness may be entirely conditional upon the activities of the 

 cerebrum, while at the same time this feeling of relation may depend 

 upon the cerebellum. My meaning is that, though consciousness have 

 its sole physical antecedent in the cerebrum, the special form of con- 

 sciousness now under consideration may be impossible of origination 

 in the cerebrum without the anatomical and physiological integrity of 

 the cerebellum. Before examining the evidence concerning the func- 

 tions of the cerebrum, a few words should be said with regard to the 

 optic lobes or corpora quadrigemina, the corpora striata, and the optic 

 thalami. The optic lobes are central organs connected with vision. 

 There seems no sufficient reason to doubt the results of experiment 

 as stated by Fenner : " The more prominent effects of destructive lesions 

 of the optic lobes in the various animals seem to be blindness, paralysis 

 of irido-motor and some oculo-motor reactions, disorders of equilibrium 

 and locomotion, and in frogs, and apparently in other animals, annihi- 

 lation of certain forms of emotional expression." 



If the higher brain-masses be removed, animals show reflex reac- 

 tions to rays of light, and, more than this, they display other bodily 

 movements evidently due to the influence of light. According to 

 Longet, birds will follow a burning candle with their heads, and frogs 

 that have been startled into movements of flight by irritation of the 

 skin will avoid objects placed in their way. 



These lobes are exceedingly sensitive to electrical stimulation, and 

 the results vary as the electrodes are placed on the anterior (nates) or 

 posterior (testes) eminences. 



Stimulation of the nates causes wide dilatation of the opposite 



